In a telecommunications network, a connection is setup between a calling party (A-subscriber) and a called party (B-subscriber), by the A-subscriber dialling or entering a subscriber number. The information contained in the subscriber number results in the setup of the connection from the A-subscriber to the telecommunications means of the B-subscriber, for instance to a telephone, a facsimile apparatus or a modem, via various subscriber switching stations in the telecommunications network. In a known network, a given subscriber number will thus always result in establishing a connection to the same communications means owned by a given subscriber.
Such usage of a subscriber number presents a problem when the A-subscriber is not interested in being connected to a particular B-subscriber, but wishes instead to be connected to any B-subscriber whatsoever who is associated with or located in a particular geographical area and possibly also belongs to a particular category of subscriber. When the telecommunications network includes a radio network comprising mobile or cordless (wireless) radio stations, the A-subscriber never knows which persons can be reached in a given geographical area at a given point in time, since the B-subscribers constantly move within the area covered by the radio network. The A-subscriber may therefore be forced to make several attempts before finding a B-subscriber who is located in the desired geographical area and who belongs to the desired subscriber category. It is also necessary for the A-subscriber to be acquainted with all subscriber numbers of all conceivable B-subscribers. Furthermore, it is not possible for the A-subscriber to reach several B-subscribers with the use of solely one subscriber number.
EP 0,431,453 discusses this problem and describes a communications radio system which can be used in airports for instance. In order to establish communication between two parties, of which the called party works with a certain aircraft, there is used a number and an object sign which denotes personnel category and aircraft. For instance, when wishing to speak with the person refuelling Pan Am's flight 743, the object sign 23-743 is entered. The first digit denotes the airline (Pan Am), the second digit denotes the occupation of the person paged (gasoline truck driver) and the last three digits denote the aircraft being refuelled (flight 743). This enables the calling party to speak with someone who fulfils certain conditions, rather than with a separate person. For instance, when the calling party is only interested in speaking to a gasoline truck driver, irrespective of the airline with which he/she is employed and irrespective of aircraft, an object sign 03-000 is inserted. In this case, the zeros function as so-called jokers or wild cards. One drawback with this system is that the called party (the gasoline truck driver employed by Pan Am) must manually insert information into the system each time he commences a job, wherewith the system is informed of the nature of the work involved and the identity of the aircraft on which work is to be performed. The called party must also inform the system when the work has been completed.
U.S. Patent Specification U.S. Pat. No. 5,224,150 describes a person-paging system which includes a plurality of central stations, each of which controls a number of pagers. Each central station includes a profile or list of transmission services for each pager associated with a respective central station. Among other things, the profile includes a list of identification numbers to which the pagers are receptive, therewith enabling a caller to transmit a paging message to one or more pagers.
U.S. Patent Specification U.S. Pat. No. 4,399,555 describes a radio telephone system which provides both conventional subscriber radio telephony and a radio telephony service of the dispatch type. A dispatch unit is able to communicate with several of the mobile units associated with the dispatch unit. The mobile units may be located in or in the vicinity of one of the cells that covers the total geographical area within the interest area of the dispatch unit. The interest area may be the total cellular traffic area or a part of said total area. The dispatch unit utilizes one or more codes to call all mobile units or a predetermined number of the total number of mobile units.